Pedilanthus plant named ‘Chilly Willy’

ABSTRACT

A new and distinct  Pedilanthus macrocarpus  named ‘Chilly Willy’ is characterized by freeze hardiness (at least to 12° F.) beyond that of any cultivars of  Pedilanthus  known to the Inventor. The color of the mature stems is R.H.S. Colour Chart 143A to 143D.

Latin name: Pedilanthus macrocarpus.

Varietal denomination: Chilly Willy.

BACKGROUND OF THE INVENTION

Pedilanthus is a genus of the large plant family Euphorbiaceae. About 15species of Pedilanthus are known from the warm parts of Mexico, rangingin growth form from small shrubs to small trees. The present inventionrelates to a new and distinct cultivar of Pedilanthus macrocarpus, ashrubby succulent species which grows wild in the Sonoran Desert in theMexican states of Sonora, Baja California Sur and Baja California Norte.Plants have also been found outside the Sonoran Desert in the Mexicanstate of Sinaloa, south of Sonora. Pedilanthus macrocarpus is commonlygrown as a succulent landscape shrub in much of the warmer parts of thesouthwestern United States. Many unpatented clones of Pedilanthusmacrocarpus are produced and sold in the nursery trade. Until thepresent time, cultivation of this species has been limited by itsminimal frost resistance, with plants showing injury at temperaturesbetween 25 and 30 degrees Fahrenheit (F). The new cultivar wasdiscovered as a naturally occurring stem mutation of an unnamed cultivargrowing in a cultivated area near Tucson, Ariz., uninjured by a historicfreeze and is the object of this application.

SUMMARY OF THE INVENTION

Among the features that distinguish the new Pedilanthus macrocarpuscultivar from all other available and commercial varieties ofPedilanthus macrocarpus known to the inventor are the followingcombination of characteristics: demonstrated freeze hardiness to atleast 12 degrees Fahrenheit, upright form and mature stem color (RoyalHorticultural Society (R.H.S.) Colour Chart 143A to 143D).

The propagation procedure is as follows: Stems are cut into 3 inch longpieces with at least one node that can be placed below the soil line.Cuttings are set into Carefree Jiffy™ peat substrate without rootinghormone and placed in flats in a standard greenhouse with a minimumnighttime temperature of at least 50 F and warming to up to as warm as100 F during the day. Rooting is completed within about 8 weeks.

The foregoing characteristics and distinctions come true to form and areestablished and transmitted through succeeding propagations. The presentinvention has not been evaluated under all possible environmentalconditions, such that the phenotype may vary with variations inenvironment without a change in the genotype of the plant.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying photographs illustrate Pedilanthus macrocarpus growingnear Tucson, Ariz., depicted in color as nearly correct as it ispossible to make in a color illustration of the character.

FIG. 1 shows a three year old Pedilanthus macrocarpus ‘Chilly Willy’growing near Tucson, Ariz.

FIG. 2 shows the flowering structure of Pedilanthus macrocarpus ‘ChillyWilly’.

DETAILED PLANT DESCRIPTION

The following is a detailed description of the new Pedilanthus plantbased upon one, two and 3 year old plants growing outdoors near Tucson,Ariz. The color descriptions are based upon the 5^(th) edition R.H.S.Colour Chart. Color names other than common usage are as listed in COLORUniversal Language and Dictionary of Names, by Kenneth L. Kelly andDeane B. Judd; National Bureau of Standards special publication 440.Washington, D.C.: U.S. Department of Commerce, National Bureau ofStandards, December 1976.

-   Plant name: ‘Chilly Willy’.-   Species: Pedilanthus macrocarpus.-   Mature plant size: 5 feet tall×5 feet wide.-   Plant growth form: A succulent, mostly leafless shrub with    clustered, upright stems. Plant exudes milky sap when injured.-   Stems: Terete, constricted at the base of each growth flush, 3-17 mm    in diameter; color varies from 143A to 143D on mature stems to 164A    on sunward new growth. Stem tips are generally rounded, sometimes    acute. Stems when young are covered with fine, appressed woolly    hairs, becoming mostly glabrous, scabrous at maturity. The stems are    fairly densely covered with slightly raised white (N155D) stomates,    approximately 80 μm across.    -   -   Leaf scars.—Half circular to crescent shaped, the rounded            side facing basally, 1 mm high×2 mm wide, containing 3            bundle scars, evenly spaced, color 173C when fresh,            weathering to N155A.-   Leaves: Alternate, short petiolate-sessile (petioles to 4 mm long),    semisucculent, lanceolate, upcurved to upwardly enrolled, 3 mm    long×1.5 mm wide to 30 mm long×3-4 mm wide, rapidly becoming    caducous with stem maturity or drought. Leaf color varies from 143C    on new growth to 53C as leaves become senescent.    -   -   Leaf margins.—Somewhat undulate, obscurely toothed. Leaf            surface: nearly glabrous, with scattered appressed woolly            hairs.-   Flowering: Inflorescence a highly modified zygomorphic cyathium,    more or less shark (crescent) shaped, with the peduncle attachment    at the shark's dorsal fin. Cyathia arise from the axils of leaves,    usually singly, occasionally paired. Flowering occurs predominantly    on the upper portion of the plant, with scattered cyathia elsewhere.    Flowering peaks primarily in spring-early summer, although it may    occur to some extent throughout the year. The cyathium internally    consists of two chambers, a hollow apical nectiferous chamber that    leads to a pore on the ventral surface of the cyathium (face of the    flower-like structure), where a drop of nectar forms; the second,    basal chamber contains numerous unistaminous and one oviferous    flower, all of which become exserted from the chamber at maturity.    Cyathium measures 32 mm long×7 mm thick, crescent-like in profile,    with a basal, more or less obconical bulge (10 mm long×7 mm wide),    color 32B. Bulge somewhat radially wrinkled, covered with scattered,    mostly appressed, fine, woolly hairs. Bulge offset abaxially from    the center by about 15 degrees, obtusely connected to the terminus    of the peduncle, the terminus measuring 5 mm high×4 mm wide×2 mm    long. Upper lobe of cyathium (color 32B) is dorsally compressed,    crestlike, the tip undulate, hollow and nectiferous internally with    an adaxial central groove extending from near the distal tip to the    bulge. Several secondary grooves (3-4) run parallel to the central    grove. The face of the upper cyathium (color 32A-32C) has a central    rounded longitudinal ridge, with parallel depressions on either    side. The nectar chamber terminates in a pore on the face of the    cyathium, just above the central portion of the face where a clear    nectar drop accumulates to attract pollinators. The center of the    face displays two rounded, grooved, downward facing lobes that form    an apparent landing platform (color 179B). Lower lobe of cyathium    skirtlike (color grading from 32B to 1C), internally containing the    receptacle for the staminous and oviferous flowers, open ventrally    on the abaxial side and face, the skirt two sided, deltoid laterally    and extending downward, with a rounded tip, margin entire. Interior    to the skirt lies another membranous layer with a ciliate margin    partially visible on an open cyathium. This membrane is attached to    the upper lobe of the cyathium and tapers into a flattened linear    structure with a rounded end facing downward inside the cyathium,    this structure 7 mm long×2 mm wide, color 62A along the midrib, 62D    elsewhere.    -   -   Peduncle.—Terete, 9 mm long×1.3 mm in diameter, curving from            nearly upright to lateral or slightly descending, color 43D,            appearing glabrous, slightly waxy, but with scattered,            nearly appressed, fine woolly hairs. The unistaminous            flowers (about 20) are produced in succession over an            extended period, starting just after the exsertion of the            female flower. The female flower is exserted basally, just            below the peduncle, while the stamens are exserted            abaxially, at the basal lobe of the cyathium.-   Staminous flowers: Unistaminous, stamens 4.25 mm long at maturity,    1.25 mm×1.25 mm anther (32B), 3 mm long×⅔ mm thick filament (45A);    pedicel 14 mm long×⅔ mm thick at maturity, color 62D or lighter.    Anthers change to color N92A after dehiscence, shrinking to 1    mm×1 mm. Stamens abscise from pedicels within 2-3 days after    anthesis. Pollen color 13D.-   Pistillate flowers: Ovary lanceoloid, glabrous, 13 mm long×3 mm    thick at anthesis, color apically 43D, near base 43B, basally 3 low    ribs, about 4 mm long and ⅓-½ mm wide.    -   -   Base.—Glandular, the 3 glands alternating with the ribs.            Gland color 1D. Ovary connection to pedicel tapered acutely.            A ring of color 43C can be seen at this junction. Style            glabrous, tapers from 1.5-1 mm×4 mm long, color 43A. Stigma            glabrous comprised of 3 conical lobes which vary from            apically extended to somewhat reflexed, tapering from 0.3 to            0.4 mm thick×4 mm long and tapering to a point, color 43A.            Pistillate flower pedicel hooked, 14 mm long×1.5 mm thick at            anthesis, color 149D or lighter, glabrous, obscurely grooved            longitudinally (about 10). Fruit a loculicidal 3 seeded            capsule. No capsules or seeds were available at the time of            description.

COMPARISONS TO RELATED PEDILANTHUS

The color seen in Pedilanthus macrocarpus stems typically ranges frompale yellow green (192A) to brilliant yellow green (N144B). ‘ChillyWilly’ stems normally range in color from 143A to 143D on typical stemsto 164A on sunward new growth. Pedilanthus macrocarpus clones vary fromshort, very tight, vertically clustered forms to rather rangy, archingforms up to 6 ft or more in height and spread. ‘Chilly Willy’ is anintermediately sized form, rarely over 5 feet in size, moderatelytightly clustered, with only a small tendency to produce arching stems.Pedilanthus macrocarpus flowering structures commonly vary in color from32B to about N30A. The predominant flower color of ‘Chilly Willy’ is32B. Pedilanthus macrocarpus normally is damaged by temperatures varyingfrom 28° F. to 25° F. Severe damage or death normally occurs when theseplants are exposed to temperatures below 20° F. ‘Chilly Willy’ wasselected from a plant that had survived repeated freezes from 13-15° F.without damage. Open grown plants of Chilly Willy have survived with nodamage at a documented temperature of 12° F. while other unrelatedplants were killed.

I claim:
 1. A new and distinct Pedilanthus macrocarpus plantsubstantially as described and illustrated herein.